Introduction: Delayed or absent puberty is thought to be common in boys with Duchenne Muscular Dystrophy (DMD).
Objective: To evaluate testicular development, function and puberty in DMD in a 12 months prospective longitudinal study.
Methods: Thirty-four boys had assessment of puberty and testes volume by a single endocrinologist. Testes volumes were converted to Z-scores adjusted for bone age. Boys were divided into group A [Baseline age<11.5 years: median 9.1 years (6.4, 11.4)] and group B [Baseline age ≥1.5 years: median age 14.9 (11.8,16.8)]. Results expressed as median (range).
Results: At baseline, 17/20 (85%) and 13/14 (93%) of Group A and B were on GC for a duration of 3.3 years (0,8.2) and 8.5 years (3.7,13.4), respectively. In Group A, median testes volume Z-scores at baseline and 12 months were −0.6(−3.6,+1.5) and −2.0(−3.6,+1.7), respectively [P=0.04]. In Group B, median testes volume Z-scores at baseline and 12 months were −1.6(−3.3,+0.8) and −2.3(−3.3,+0.8), respectively [P=0.31]. At baseline and 12 months, 3/14 (21%) and 4/14 (29%) in Group B were on testosterone. By 12 months follow-up, 9/14 (64%) of Group B had testes volume <4 ml, including 5/9 (56%) boys who were on testosterone. Testosterone levels were undetectable at baseline and 12 months in the 4 boys who remained pre-pubertal. LH was undetectable at baseline in these 4 boys; whereas 3 had undetectable LH at 12 months, with another boy with LH of 0.6 U/L. By 12 months, 5/14 (36%) of Group B had signs of puberty (testes volume ≥4 ml). 7/9 (78%) in Group B who had testes volume <4 ml were on daily Deflazacort whereas 1/5 (20%) in Group B had testes volume ≥4 ml whereas 1/5 (20%) were on daily Deflazacort. Impalpable testes were reported in 7/34 (21%) of the total cohort during 12 months period. Of these, 6/7 (86%) were retractile; 1/7 (14%) had bilateral inguinal testes throughout the follow-up period, confirmed on testes ultrasound.
Conclusion: This first longitudinal study with clinical examination of testes showed that DMD boys have relatively small testes even after adjusting for bone age. This suggests the possibility of functional hypogonadotrophic hypogonadism given the low LH and testosterine.Spontaneous puberty is uncommon, observed in only 36% of older adolescents. Pubertal disorders may be commoner in boys treated with Deflazacort. Our study documented a relatively high frequency of impalpable or retractile testes in DMD for the first time.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology